抄録
Electron microscopy revealed that, although both thick and thin filaments are present, Z-band and myofibrillar organization are totally lost in indirect flight muscle (IFM) of a Drosophila muscle mutant wings-up B (wup B). The Z-band deficiency correlates well with the gene dosage; in wup B/wup B+ heterozygotes, normal internal structure of the Z-band is restricted only within the central core of the myofibrils. Two-dimensional gel electrophoresis (O'Farrell 1975) revealed that nine myofibrillar proteins are either absent or reduced in the indirect flight muscle of the mutant. Some of the anomalies are not restored in heterozygotes. These observations suggest a possibility that the product of wup B+ gene is one of the Z-band components, without which the regular arrangement of thick and thin filaments cannot be maintained. Possible mechanisms for the fact that a single mutation causes multiple changes on the gel are discussed. We concluded that absence of one component causes disappearance or reduction of others which are functionally and/or structurally related.
